Method of making a ball bearing



Feb. 18, 1958 H. 1... POTTER 2,823,449

METHOD OF MAKING A BALL BEARING Filed April 13, 1953 INVENTOR Howell l1. Poikz BY 1 v ATTORN EYS United States Patc t r 2,823,449 METHOD on MAKING A BALL BEARING Howell'L, Potter, New Britain, Conn., assignor to The Fafnir Bearing Company, New Britain, Conn., a. corporation of'Connecficut ApplicationApril 13, 1953,.Serial No. 348,299 6 Claims. .(Cl. 29-1484) My invention relates to -an'tifriction bearings and in particulartoa method of forming 'filler slots in -race-ring constructionstherefor. -T-his application is a continuation-in-part of my application Series No. 72,346 filed January 24, 1949, now Patent No. 2,643,165.

In antifriction bearings in-which the race grooves are defined by opposed generally radially extending walls,

it is customary to provide-filler-slots in one or both of" the adjacent 'end'o f :the bearing ring, but suchconstruction provides 3"diSCOhill1ll0US 'outer surfa'ce' on the inner ring soas to render untea'sible the relatively inexpensive grinding of the ringon a'centerless grinder; this construc tion al'so'rendersunfea'si ble the application of a-seal to run on the slottedsidebf thebearingring. In accordance withthe other construction, theout'er surface of one end'of'the inner ring is turned down to a -diameter slightly less than the diameter of the bottom'o'f-th'e'racc groove, andthis turned-down end extends from the edge of the race-groove to the end of the ring. An axial filler slot is then cut in the barrier between this turned down end and i the race groove. Even though this second method of construction may-permit the application of a seal between the bearingrings, the outer turned down end of the inner ring-is-rendered-unnecessarily weak and the turned down -end-is-usuallyrough-and unsatisfactory for receiving .acont-acvseal.

' It is, accordingly, an object of the invention to provide an improved method of forming a -filler slot inia bearing ring.

It is another object to provide an improved method of forming an inner-bearing-ring construction wherein a filler slot may be provided for insertion of antifriction elements, said method involving the removal of a minimum of material after hardening.

Other ob ects and various further features of the invention will be pointed out or will occur to those skilled in the art from a reading of the following specification in conjunction with the accompanying drawings. In said drawings, which show, for illustrative purposes only, preferred methods:

Fig. 1 is a fragmentary sectional view through an antifriction bearing incorporating features of the invention, the parts being shown during an assembly operation;

Fig. 2 is a fragmentary sectional view of the inner ring of Fig. 1, during the process of making said inner ring;

Fig. 3 is a more or less plan view of the part of the inner ring which is shown in Fig. 2;

Fig. 4 is a view similar to Fig. 3, after a further step in the manufacture of the inner ring of Fig. 1; and

Figs. 5 and 6 are sectional views similar to Fig. 2, illustrating modifications.

slots, such as the :slot 10 Briefly stated, my invention contemplates-an improved "filler slot'construction and method ofr-making the same.

a limited recess in said recess being The slot may be formed by providing the outer surface of the inner ring,

' located between 'the'race groove; and'the adjacent end of vthe ring, and the ring may be cutaway between-the recess and the-groove.

In" the methods tobe "described, ,therecess is provided by making a shallow bore, groove or .flat'in'the outer surface of'thering' and adjacentone side of the racefgroove. ,Theiring material between thebore,

groove or fiat and the v groove may then be cut "away," as by. a grinding operation, after hardening 'and after "the race groove and the outer'ringsurface havebeen ground to the desired finish.

.Referring to'the drawings, myinve'ntionis shown in 2 application to an antifriction bearing; including :aninner ring 5, an outer ring 6, and ball-type antifriction elements 7. ,Thegan'tifriction elements 7 may run in an outer race groove s airs in an inner race groove'9 having lateral walls extending generally radially. Ball-insertion or filler in the outerrring 6, maybe f ground or"oth'erwise-formed atone location on each ring.

' In accordance "with the invention, ,1 provide 7 a ;novel method of forming an insertion or'filler slot means in the inner ring.5"'so'as-:not'to greatlyg-impair the. strength of the inner'ring'and" to permit ringgrindingon' a centerless grinder and soas'also-topermit the application of seal 5 -6 on the insertion side lot, in the" form shown recess 11 may be simply .formed'as a shall'ow"bore or hole extending generally ,lip or wall 13, of the race, groove mum. Thebore 11 radially and preferably near; on 9. .The bore 11.may sharpened slightly. flatter, at the point 'the;drill may be run to a'depth and preferably slightly-below This drillingoperation may be 5 issubjected to hardening and, groove is finish-ground; and,

be made by a "drill effected before the. ring therefore, before the race 'since the ring material betwen the bore 11 and'the race groove 9 is 'to bev cut away after hardening, I prefer'that the amount of materialthen removed shall.be a miniis thus .jpreferably drilled as close as is tolerable .to the wall 13Pof;the groove9. "The' bore. 11 may also be of such .diameter or solongitudinally located that the outer end'or lip 11' thereofmay'provi'de adequate clearance-forthe -inser'tion*o'f---a* ball, as indicatedby-- the dot-dash outline 7' of a ball 7 in the process of insertion.

As has been implied above, the insertion or filler slot of the inner ring 5 may be completed by a grinding step to take place after hardening and after the race groove 9 and the outer surface of the ring 6 have been finishground. I have found that this final removal of slot material may be very effectively accomplished by a grinding wheel of relatively large radius, as indicated by the dot-dash outline 14 of Fig. 1. The wheel 14 may be spun on an axis generally at right angles to the axis of the ring 5, and there need be no chucking of the inner ring to accomplish this final grinding step. In practice, the inner ring is placed face down on a table and brought up against the grinding wheel 14, which is spun on a horizontal axis. Once this axis has been properly adjusted for spacing above the table, the slot cut is properly located; and, as grinding proceeds, the operator need merely oscillate the inner ring from side to side about the face of the wheel in order to generate the desired shape. Of course, the insertion slot may be made to enter upon the race groove 9 at any desired location by adjustment of the placement of the grinding wheel axis, but, in the preferred form shown, the recess or groove 15 cut away by the grinding wheel 14 terminates short of the p int described in connection with Fig. 1.

of maximum depth of the groove 9 so as to leave a very small barrier over which the balls are snapped and the groove 9 provides an uninterrupted raceway for the balls inthebottom thereof. 3 ,1

It will beclear that I have described animproved insertion or filler slot construction and an improved method of forming the same. Since the slot does not run out to the face or end of the ring, there is an uninterrupted cylindrical surface on which a seal may berun;

this could be a regular felt seal, a pressed or slinger-type seal, or the outer surface of the ring 5 could be grooved (as schem atically indicated by dotted-lines 16 in Fig. 1)

for the accommodation of aresilient seal of the type described in the copending application of Leisteret al., Serial No. 291,704 filed June-'4, 1952, now Patent No. 2,764,432.- Because of the above-mentioned uninterrupt'ed cylindrical surface at the end 12, it is possible to grind the outer surface of the ring 5 on a center-less grinder-after making the bore 11 (before hardening) and after hardeningyby using a centerless grinder it will -be appreciated that the costmay be reduced substantially sincethe present method requires mounting the inner ring on an arbor in a cylindrical grinder. Aside from the above-noted features of better adaptability to seals and of cheaper grinding, my improved construction makes possibleconsiderable savings in machining, for the bore or hole 11 can be drilled more quickly than the conventional slot canbe milled, andthe drill can be easily resha'rpene'd so as to last for an indefinite time, whereas mills wear out relatively 'rapidly and are expensive and difiicult to sharpen.

.While the method described in connection with 'Figs'. 1

about as closely. The groove 20 is preferably turned'in the ring when it is being machined but the groove 20 could be made otherwise and would not have to extend completely around the ring. The barrier 21 between" the groove 20 and raceway 9' would be ground down as shown in Fig. l to provide the filler slot as illustrated and In the formshown in Fig. 6, instead of the hole as in Fig. l or the groove as in Fig. 5, a flat 22 is milled or otherwise formed in the outer surface of the ring between theraceway and the-adjacent end of the ring. Such a flat would function in much the same manner as the groove and would leave a barrier 23 corresponding to the barrier 21 of Fig. 5. The barrier 23 could be ground down as heretofore described to form a filler slot.

While I have described my invention in detail for the preferred methods and forms. shown, it will be understood that modifications may be made within the scope of the invention as defined in the appended claims.

I claim: 7

' 1. The method of making an inner bearing ring of the character indicated from a cylindrical annular ring blank, which comprises forming a circumferential race groove, between the ends of said ring, boring said ring between the race groove and one end of said ring, hardening said ring, finish-grinding the race groove, and grinding away a passage between the bore and the race groove.

2. The method of forming a filler slot in a bearing ring having a raceway groove therein, which comprises, formto 4 is a preferred one, other methods or variations may e be made..-..

ing a generally radial depression in the ring near the raceway groove and spaced from the adjacent end of the I bearing ring so as to leave a relatively thin barrier between the depression and the raceway groove, finish-grinding said race groove, and cutting the barrier to form a filler slot from said depression to said groove.

3. The method of forming a filler slot in a bearing ring having a raceway groove therein which comprises forming a generally radial depression in said ring adjacent the raceway groove and terminating substantially short of the adjacent end of the ring, and cutting the barrier between said raceway groove and the depression to form the filler slot. H

4. In the combination defined in claim 3, the step of forming a generally radial depression, comprising drilling a generally radial hole in said ring.

5. In the combination defined in claim 3, the step of forming a generally radial depression, comprising turning a circumferential groove in said ring.

6. In the combination defined in claim 3, the step of forming a generally radial depression, comprising slabbing off a flat on said ring.

References Cited in the file of this patent UNITED STATES PATENTS -0s plack Apr. 5, 1949 

